#include <iostream>
#include <windows.h>
using namespace std;
const float PI=3.1415926;

class Circle
{
    private:
    float radius;

    public:
    float circumference(float r);
    float area(float r);

    Circle(float r);
};

Circle::Circle(float r = 0)
{
    radius=r;
}
float Circle::circumference(float r)
{
    float Circle_C = 2*PI*r;
    return Circle_C;
}
float Circle::area(float r)
{
    return PI*r*r;
}

int main()
{
    SetConsoleOutputCP(CP_UTF8);
    float r;
    cout<<"请输入圆的半径：";
    cin>>r;
    Circle cir(r);
    cout<<"圆的周长为："<<cir.circumference(r)<<endl;
    cout<<"圆的面积为："<<cir.area(r)<<endl;
    system("pause"); 
    return 0;
}